Meson-exchange currents and final-state interactions in quasielastic electron scattering at high momentum transfers

The effects of meson-exchange currents (MEC) are computed for the one-particle one-hole transverse response function for finite nuclei at high momentum transfers q in the region of the quasi-elastic peak. A semirelativistic shell model is used for the one-particle-emission (e,e') reaction. Relativistic effects are included using relativistic kinematics, performing a semirelativistic expansion of the current operators, and using the Dirac-equation-based (DEB) form of the relativistic mean-field potential for the final states. It is found that final-state interactions (FSI) produce an important enhancement of the MEC in the high-energy tail of the response function for q≥1 GeV/c. The combined effect of MEC and FSI goes away when other models of the FSI, not based on the DEB potential, are employed.DGI (Spain) (Grant Nos. FIS2008-01143, FPA2006-13807-C02-01, FIS2008- 04189, and FPA2007-62216)Junta de AndalucíaINFN-MEC (Spain)Spanish Consolider-Ingenio 2000 Program CPAN (CSD2007-00042